CN115559815A - Engine bleed air recompression cooling system based on CCA technology - Google Patents

Abstract

The invention provides an engine bleed air recompression cooling system based on a CCA technology, which comprises: the bleed air cooling and recompression flow path comprises a heat exchanger and a recompression air compressor; the engine bleed air recompression cooling system based on the CCA technology not only can greatly reduce the bleed air temperature of the high-pressure compressor, but also can compensate and improve the bleed air loss and improve the quality of the cooled bleed air.

Description

An Engine Bleed Air Recompression Cooling System Based on CCA Technology

technical field

The invention relates to the technical field of aero-engine cooling, in particular to an engine bleed air recompression cooling system based on CCA technology.

Background technique

Improving thrust and thermal efficiency has always been the goal pursued by aero-engine designers. According to the basic principles of thermodynamic cycle, increasing the boost ratio and the temperature before the turbine are the key technical ways to improve thrust and thermal efficiency. However, with the continuous increase of the turbocharging ratio and the maximum temperature before the turbine of the aero-engine, the thermal protection of the aero-engine faces great challenges: on the one hand, the increase in the temperature before the turbine increases the cooling requirements of the hot-end components, and on the other hand, the overall pressure ratio The increase of the temperature of the cooling air causes the temperature of the cooling air to rise, and the quality of the cooling air available for the turbine is further reduced. The combined effect of the two makes the working environment of the hot end parts even worse. Only relying on the temperature resistance of materials and the development of cooling technology can no longer meet such stringent thermal protection requirements. . In this context, cooling cooling air (CCA) technology, which can greatly improve the cooling quality of cooling air and realize the comprehensive utilization of engine energy, has become one of the key ways to solve the above problems, and has attracted extensive attention from academia and industry.

CCA technology, full name of cooled cooling air, also known as cooling cooling air technology, usually the heat sink used in CCA technology includes engine external air, aviation kerosene and ram air, etc., through the above-mentioned low-temperature working fluid from the high pressure compressor HPC) outlet bleed air extracts heat, thereby improving the cooling quality of cooling air, reducing cooling bleed air flow and turbine material temperature, and improving engine performance and life.

At present, scholars at home and abroad have carried out a lot of research on the technical feasibility of CCA and the design and optimization technology of CCA external heat exchangers: for example, air-air and fuel-air heat exchangers are considered to cool the compressor bleed air. Although the use of CCA technology can greatly reduce the bleed air temperature and improve the quality of the cooling bleed air, but the bleed air will cause pressure loss after passing through the heat exchanger, but the cooling air of the turbine blades must have sufficient pressure margin to enter the mainstream gas through the blade cooling holes , especially for turbine stator blade cooling, the bleed air must overcome the pressure loss flowing through the heat exchanger. Generally, the pressure loss of bleed air after passing through the air-to-air heat exchanger is usually 5% to 20%. At present, some people consider adding the ACM system (composed of a centrifugal compressor and a radial turbine) to increase the pressure of the HPC bleed air, and some people start with the conceptual design of changing the flow path of the secondary air system and introducing the bleed air into the heat exchanger. The effect of actual flight conditions on the cooling air (CCA) system was evaluated, and a transient analysis of the CCA heat exchanger under stress temperature rise was performed. But so far, no ideal method has been found that can not only greatly reduce the temperature of the bleed air of the high-pressure compressor, but also improve the total pressure loss of the bleed air.

Contents of the invention

The invention designs an engine bleed air recompression cooling system based on CCA technology to improve the total pressure loss of bleed air while reducing the bleed air temperature of a high-pressure compressor.

In order to solve the above problems, the present invention discloses an engine bleed air recompression cooling system based on CCA technology,

An engine bleed air recompression cooling system based on CCA technology, including:

A bleed air cooling and recompression flow path, which includes a heat exchanger and a recompression compressor;

bleed air from the high pressure compressor is divided into a first portion of bleed air and a second portion of bleed air, wherein the first portion of bleed air enters the bleed air cooling and recompression flow path, in the bleed air cooling and recompression flow path After the cooling and recompression treatment, the second part of the bleed air discharged from the high-pressure compressor is mixed and discharged through the ejector, and then the formed bleed air is used to cool the high-temperature hot-end components.

Further, the engine bleed air recompression cooling system also includes:

The bleed air direct discharge flow path is connected in parallel with the bleed air cooling and recompression flow path, the second part of bleed air from the high-pressure compressor enters the bleed air straight discharge flow path, and flows through the bleed air straight discharge flow path After the flow path, the first part of bleed air discharged from the bleed air cooling and recompression flow path is mixed with the ejector and then discharged.

Further, the engine bleed air recompression cooling system also includes:

The bleed air input pipe, the bleed air from the high-pressure compressor enters the engine bleed air recompression cooling system through the inlet port of the bleed air input pipe;

A diverter valve, the outlet end of the bleed air input pipe is connected to the inlet of the diverter valve, and the outlet of the diverter valve is respectively connected to the bleed air cooling and recompression flow path and the bleed air straight discharge flow path. The bleed air of the compressor is divided into the first part of bleed air and the second part of bleed air after passing through the diverter valve.

Further, the heat exchanger includes:

A precooler, which uses the first cooling medium as a heat sink to cool the first part of the bleed air;

A subcooler, which uses a second cooling medium as a heat sink to cool the first part of bleed air;

The first part of bleed air first enters the pre-cooler for pre-cooling, and then enters the sub-cooler for re-cooling.

Further, the first cooling medium is external air.

Further, the second cooling medium is fuel oil.

Further, the precooler, the recompression compressor and the subcooler are arranged in sequence, and the first part of bleed air flows through the precooler, the recompression compressor and the subcooler in sequence.

Further, the precooler is an air-to-air heat exchanger, and the precooler is arranged in the engine outer duct;

The subcooler is an air-oil heat exchanger, and the subcooler is arranged in the compartment between the inner and outer ducts.

Further, the engine bleed air recompression cooling system also includes a first cooling medium flow path, and the first cooling medium flow path includes:

A first cooling medium input pipe, the first cooling medium is input into the first cooling medium flow path through the inlet end of the first cooling medium input pipe;

A splitter ring, the inlet of which is connected to the outlet end of the first cooling medium input pipe;

The first cooling medium branch pipe 1, its inlet end is connected to one of the outlets of the split ring, and the outlet end is connected to the cold side inlet of the precooler;

The first cooling medium straight pipe, the inlet end of which is connected to the other outlet of the split ring;

The inlet end of the first cooling medium branch pipe 2 is connected with the outlet of the cold side of the precooler.

Further, the engine bleed air recompression cooling system also includes a second cooling medium flow path, and the second cooling medium flow path includes:

The second cooling medium input pipe, the second cooling medium enters the second cooling medium flow path through the inlet end of the second cooling medium input pipe, and the outlet end of the second cooling medium input pipe is connected to the subcooler The cold side inlet connection of the;

The inlet end of the second cooling medium output pipe is connected to the cold side outlet of the subcooler.

The engine bleed air recompression cooling system based on CCA technology described in this application has the following advantages:

First, by dividing the bleed air from the high-pressure compressor into two parts, that is, the first part of bleed air and the second part of bleed air, while realizing the adjustment of the temperature and pressure of the bleed air, on the one hand, it can reduce the number of heat exchangers and recompressed compressed air. The size and weight of the engine can reduce the loss of thrust-to-weight ratio of the engine. On the other hand, it can increase the heat exchange effect with the external air, increase the heat transfer efficiency of the heat exchanger and compensate for the total pressure loss;

Second, use the air-air precooler and air-oil recooler for the first part of the bleed air to perform two-stage heat exchange, which can finally greatly reduce the overall bleed air temperature of the high-pressure compressor;

Third, the first part of the bleed air uses recompression technology to compensate or increase the total pressure loss of the bleed air, thereby ensuring the recovery coefficient of the total pressure of the bleed air and the external culvert air. The heat transfer effect of the cooler;

Fourth, finally, by improving the cooling quality of the bleed air, the cooling effect of the hot-end parts of the engine can be improved, and the thrust performance and thermal efficiency of the engine can be improved.

In short, the engine bleed air recompression cooling system based on CCA technology described in this application can not only greatly reduce the temperature of the high-pressure compressor bleed air, but also can compensate and increase the total pressure loss of the bleed air and improve the quality of the cooling bleed air.

Description of drawings

Fig. 1 is the structural representation of the engine bleed air recompression cooling system based on CCA technology described in the present invention;

Fig. 2 is a schematic diagram of the airflow distribution relationship in the engine of the engine bleed air recompression cooling system based on CCA technology according to the present invention.

Explanation of reference signs:

1. Bleed air cooling and recompression flow path; 11. Heat exchanger; 111. Precooler; 112. Recooler; 12. Recompression compressor; 13. Bleed air cooling and recompression branch pipe; 131. First Branch pipe; 132, second branch pipe; 133, third branch pipe; 134, fourth branch pipe; 14, power input transmission device; 2, bleed air straight discharge flow path; 21, bleed air straight discharge branch pipe; ; 4, diverter valve; 5, bleed air output pipe; 6, the first cooling medium flow path; 61, the first cooling medium input pipe; 62, split ring; 63, the first cooling medium branch pipe one; 64, the first cooling 65. The second branch pipe of the first cooling medium; 66. The first cooling medium output pipe; 7. The second cooling medium flow path; 71. The second cooling medium input pipe; 72. The second cooling medium output pipe; 8. Ejector; a, high-pressure turbine; b, high-pressure compressor; c, engine bleed air recompression cooling system; d, mixer one; e, combustion chamber; f, fan; g, mixer two; h, Low-pressure turbine; j, mixing chamber; k, low-pressure shaft; m, high-pressure shaft.

detailed description

In order to make the above objects, features and advantages of the present invention more comprehensible, specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

Example 1

As shown in Figure 1, an engine bleed air recompression cooling system based on CCA technology includes:

Bleed air cooling and recompression flow path 1, which includes a heat exchanger 11 and a recompression compressor 12;

The bleed air from the high-pressure compressor is divided into the first part of bleed air and the second part of bleed air by the splitter assembly, wherein the first part of bleed air enters the bleed air cooling and recompression flow path 1, and in the bleed air cooling and recompression After the cooling and recompression process in the flow path 1, the second part of the bleed air discharged from the high-pressure compressor is mixed and discharged through the ejector 8, and then the formed bleed air is used to cool the high-temperature hot-end components.

In this application, the heat exchanger 11 is used to cool down the first part of the bleed air, so that the temperature of the finally obtained bleed air is greatly reduced; the first part of the bleed air is recompressed by the recompression compressor 12 to improve It compensates the total pressure loss of the bleed air, thereby achieving the purpose of improving the cooling quality of the bleed air, improving the cooling effect of the hot end parts of the engine, and improving the thrust performance and thermal efficiency of the engine.

More importantly, in this application, by dividing the bleed air from the high-pressure compressor into two parts, that is, the first part of bleed air and the second part of bleed air, while realizing the adjustment of the temperature and pressure of the bleed air, on the one hand, it can Reduce the size and weight of the heat exchanger 11 and the recompression compressor 12, reduce the thrust-to-weight ratio loss of the engine, on the other hand, increase the heat exchange effect with the external air, and increase the heat transfer effectiveness of the heat exchanger 11 and Compensate for total pressure loss.

Further, the engine bleed air recompression cooling system based on CCA technology also includes:

The bleed air straight discharge flow path 2 is connected in parallel with the bleed air cooling and recompression flow path 1, the second part of bleed air from the high pressure compressor enters the bleed air straight discharge flow path 2, flows through the bleed air The first part of the bleed air discharged from the bleed air cooling and recompression flow path 1 is mixed with the ejector 8 and then discharged.

As some embodiments of the present application, the bleed air straight exhaust flow path 2 includes:

The bleed air straight discharge branch pipe 21 is connected in parallel with the bleed air cooling and recompression flow path 1 .

Furthermore, the engine bleed air recompression cooling system based on CCA technology also includes:

The bleed air input pipe 3, the bleed air from the high-pressure compressor enters the engine bleed air recompression cooling system through the inlet end of the bleed air input pipe 3;

A diverter valve 4, the outlet end of the bleed air input pipe 3 is connected to the inlet of the diverter valve 4, and the outlet of the diverter valve 4 is connected to the bleed air cooling and recompression flow path 1 and the bleed air straight discharge flow respectively. The bleed air from the high-pressure compressor is divided into the first part of bleed air and the second part of bleed air after passing through the diverter valve 4.

As some embodiments of the present application, in use, the flow ratio of the first part of bleed air and the second part of bleed air can be adjusted by controlling the opening of the diverter valve 4 .

Furthermore, the engine bleed air recompression cooling system based on CCA technology also includes:

The bleed air output pipe 5, the inlet end of the bleed air output pipe 5 is respectively connected with the outlet end of the bleed air cooling and recompression flow path 1 and the bleed air straight-line branch pipe 21, and the bleed air cooling and recompression flow The first part of the bleed air discharged from the path 1 and the second part discharged from the bleed air straight discharge flow path 2 are mixed and discharged through the bleed air output pipe 5 .

As some embodiments of the present application, the bleed air output pipe 5 and the bleed air straight-line branch pipe 21 can be two pipes arranged separately, or can be a continuous pipe. At this time, the front section of the pipe serves as The bleed air straight discharge branch pipe 21 has a rear section as the bleed air output pipe 5 .

Further, the heat exchanger 11 includes:

A precooler 111, which uses the first cooling medium as a heat sink to cool the first part of the bleed air;

A subcooler 112, which uses a second cooling medium as a heat sink to cool the first part of the bleed air;

The first part of bleed air first enters the pre-cooler 111 for pre-cooling, and then enters the sub-cooler 112 for re-cooling.

Preferably, the first cooling medium is enclosed air, and the second cooling medium is fuel oil.

More preferably, the precooler 111 is an air-to-air heat exchanger, and the precooler 111 is arranged in the outer duct of the engine. Part of the bleed.

As some embodiments of the present application, the precooler 111 includes core tube bundles and inlet and outlet connecting pipes. The precooler 111 is composed of a plurality of sub-heat exchangers, distributed in an annular shape in the outer duct, and the bleed air to be cooled Flowing in the tube, the external gas sweeps across the outside of the tube bundle.

More preferably, the subcooler 112 is an air-oil heat exchanger, and the subcooler 112 is arranged in the cabin between the inner and outer ducts, and the fuel is cooled again in the subcooler 112 to the bleed air, while improving The enthalpy value of fuel improves the comprehensive utilization of energy.

As some embodiments of the present application, the subcooler 112 includes a core tube bundle and inlet and outlet connecting pipes, and the subcooler 112 is composed of multiple sub-heat exchangers.

Further, the precooler 111, the recompression compressor 12 and the subcooler 112 are arranged in sequence, and the first part of bleed air flows through the precooler 111, the recompression compressor 12 and the subcooler 112 in sequence .

As some embodiments of the present application, the recompression compressor 12 is composed of multiple single-stage axial-flow sub-compressors, and the multiple sub-compressors are circumferentially distributed outside the outer duct.

Further, the bleed air cooling and recompression flow path 1 also includes:

The bleed air cooling and recompression branch pipe 13, the bleed air cooling and recompression branch pipe 13 sequentially connects the precooler 111, the recompression compressor 12 and the subcooler 112 together to form the bleed air cooling and recompression branch pipe 13. Compression flow path 1.

Specifically, the bleed air cooling and recompression branch pipe 13 includes:

The first branch pipe 131, its inlet end is connected to one of the outlets of the diverter valve 4, and the outlet end is connected to the hot side inlet of the precooler 111;

The second branch pipe 132, its inlet end is connected to the hot side outlet of the precooler 111, and its outlet end is connected to the air inlet of the recompression compressor 12;

The third branch pipe 133, its inlet end is connected to the exhaust port of the recompression compressor 12, and its outlet end is connected to the hot side inlet of the subcooler 112;

The inlet end of the fourth branch pipe 134 is connected to the hot side outlet of the subcooler 112 , and the outlet end is connected to the bleed air output pipe 5 .

Further, the bleed air cooling and recompression flow path 1 also includes:

The power input transmission device 14 is connected with the recompression compressor 12 and can drive the recompression compressor 12 to work.

Further, the power input transmission device 14 is transmitted to the recompression compressor 12 by taking power from the low pressure shaft or high pressure shaft of the engine, and then drives the recompression compressor 12 to re-compress the bleed air at the outlet of the precooler 111. compression.

Further, the engine bleed air recompression cooling system also includes a first cooling medium flow path 6, which includes:

The first cooling medium input pipe 61, the first cooling medium is input into the first cooling medium flow path 6 through the inlet end of the first cooling medium input pipe 61;

A splitter ring 62, the inlet of which is connected to the outlet end of the first cooling medium input pipe 61;

The first cooling medium branch pipe 1 63, its inlet end is connected to one of the outlets of the splitter ring 62, and its outlet end is connected to the cold side inlet of the precooler 111;

The first cooling medium straight pipe 64, the inlet end of which is connected to the other outlet of the splitter ring 62;

The first cooling medium branch pipe 2 65, the inlet end of which is connected to the cold side outlet of the precooler 111;

The inlet end of the first cooling medium output pipe 66 is respectively connected with the outlet ends of the first cooling medium straight pipe 64 and the first cooling medium branch pipe 2 65 .

The first cooling medium is divided into two parts by the splitter ring 62, and a part of the first cooling medium is passed into the precooler 111 to exchange heat with the first part of the bleed air to realize the first part of the bleed air. For air pre-cooling, another part of the first cooling medium is directly discharged through the first cooling medium straight discharge pipe 64 , and the above two parts of the first cooling medium are mixed in the first cooling medium output pipe 66 and then discharged.

As some embodiments of the present application, the first cooling medium straight discharge pipe 64 and the first cooling medium output pipe 66 may be two separate pipes or one continuous pipe. The front section serves as the first cooling medium straight discharge pipe 64 , and the rear section serves as the first cooling medium output pipe 66 .

Furthermore, the geometric angle change of the diverter ring 62 in the outer duct can be controlled to regulate the flow percentage of the outer duct air passing through the precooler 111, so that the precooler 111 has a higher heat transfer efficiency and a higher heat transfer efficiency. Low total pressure loss of hot and cold side airflow. As a result of the geometric angle control of the splitter ring 62, the bleed air has the highest temperature drop and a suitable total pressure. In addition, the position of the splitter ring 62 can also be adjusted so that the engine bleed air recompression cooling system described in this application can meet the temperature requirements of the heat exchanger 11 under different engine operating conditions.

Further, the engine bleed air recompression cooling system also includes a second cooling medium flow path 7, and the second cooling medium flow path 7 includes:

The second cooling medium input pipe 71, the second cooling medium enters the second cooling medium flow path 7 through the inlet end of the second cooling medium input pipe 71, and the outlet end of the second cooling medium input pipe 71 is connected to the The cold side inlet connection of the subcooler 112;

The second cooling medium output pipe 72, its inlet end is connected with the cold side outlet of the subcooler 112;

The second cooling medium enters the subcooler 112 through the second cooling medium input pipe 71, and performs heat exchange with the first part of the bleed air. The second cooling medium output pipe 72 is discharged.

Example 2

The engine bleed air recompression cooling system based on CCA technology described in this application can be used for thermal protection of high-pressure turbine blades and other high-temperature components.

As some embodiments of this application, the engine bleed air recompression cooling system based on CCA technology described in this application can be used for cooling a turbofan engine.

Specifically, as shown in Figure 2: in the air distribution relationship shown in Figure 2, the bleed air discharged from the high-pressure compressor b is cooled and compressed by the engine bleed air recompression cooling system c in the above-mentioned embodiment 1. A part of the cooling bleed air is mixed with the mainstream gas in the mixer 1d, and then used to cool the stator of the high-pressure turbine a; the other part of the cooling bleed air is mixed with the mainstream gas in the mixer 2g, and then used to cool the high-pressure turbine a; at the same time, the power input transmission device 14 extracts work from the low-pressure rotating shaft k or high-pressure rotating shaft m of the engine and transmits it to the recompression compressor 12 to drive the recompression compressor 12 to recompress the bleed air at the outlet of the precooler 111 , to compensate for the total pressure loss after the bleed air passes through the heat exchanger 11, so as to ensure that the cooling bleed air has a good cooling effect on the blades of the turbine engine. In addition, the turbofan engine also includes components such as a combustion chamber e, a fan f, a low-pressure turbine h, and a mixing chamber j.

The working process of the engine bleed air recompression cooling system based on CCA technology described in this application is described in detail below:

The bleed air flowing into the high-pressure compressor from the bleed air input pipe 3 flows into the bleed air straight discharge branch pipe 21 and the hot side inlet of the precooler 111 respectively through the diverter valve 4, and after exchanging heat with the external air in the precooler 111, the The hot side outlet of the precooler 111 enters the recompression compressor 12, and the recompression compressor 12 is driven by the power input transmission device 14 to compress the bleed air in it, and the compressed bleed air enters the hot side inlet of the subcooler 112, After exchanging heat with the fuel at a lower temperature in the subcooler 112, it flows out through the outlet of the hot side of the subcooler 112 and mixes with the bleed air in the bleed air straight discharge branch pipe 21 through the ejector 8, and then exits the bleed air output pipe 5 outflow, used to cool the high temperature hot end parts;

At the same time, after the first cooling medium, the occluded air is diverted by the splitter ring 62, part of it enters the cold side inlet of the precooler 111, and the rest continues to flow in the outer duct. After heat exchange, it flows out through the outlet of the cold side of the precooler 111, mixes with the remaining outer air in the outer duct, and then flows to the outlet of the outer duct;

In addition, the fuel oil, the second cooling medium, flows in from the cold side inlet of the subcooler 112, and after exchanging heat with the compressed bleed air in the subcooler 112, flows out from the cold side outlet of the subcooler 112, and finally enters the combustion chamber e or afterburner combustion.

It has been verified that the temperature of the bleed air flowing through the engine bleed air recompression cooling system based on CCA technology described in this application can be reduced by 100-60K, and the total pressure loss generated after the bleed air passes through the heat exchanger 11 is compensated, and the obtained The bleed air has high pressure potential energy, which can effectively cool the engine turbine blades.

In summary, it is not difficult to obtain that the engine bleed air recompression cooling system based on CCA technology described in this application has the following advantages:

First, by dividing the bleed air from the high-pressure compressor into two parts, that is, the first part of bleed air and the second part of bleed air, while realizing the adjustment of the temperature and pressure of the bleed air, on the one hand, the number of heat exchangers 11 and recompression can be reduced. The size and weight of the compressor 12 can reduce the thrust-to-weight ratio loss of the engine, on the other hand, it can increase the heat exchange effect with the external air, increase the heat transfer efficiency of the heat exchanger 11 and compensate for the total pressure loss;

Second, use the air-air precooler 111 and the air-oil recooler 112 for the first part of the bleed air to perform two-stage heat exchange, which can finally greatly reduce the overall bleed air temperature of the high-pressure compressor;

Third, the first part of the bleed air uses recompression technology to compensate or increase the total pressure loss of the bleed air, thereby ensuring the recovery coefficient of the total pressure of the bleed air and the external culvert air. The heat exchange effect of the subcooler 112;

Fourth, finally, by improving the cooling quality of the bleed air, the cooling effect of the hot-end parts of the engine can be improved, and the thrust performance and thermal efficiency of the engine can be improved.

To sum up, it is not difficult to obtain that the engine bleed air recompression cooling system based on CCA technology described in this application can not only greatly reduce the bleed air temperature of the high-pressure compressor, but also can compensate and increase the total pressure loss of the bleed air, and improve the cooling efficiency of the bleed air. air quality.

Although the present invention is disclosed above, the present invention is not limited thereto. In the description of this specification, references to the terms "one embodiment," "some embodiments," "exemplary embodiments," "example," "specific examples," or "some examples" are intended to mean that the implementation A specific feature, structure, material, or characteristic described by an embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, so the protection scope of the present invention should be based on the scope defined in the claims.

Claims (10)

1. An engine bleed air recompression cooling system based on CCA technology, comprising:

a bleed air cooling and recompression flow path (1) comprising a heat exchanger (11) and a recompression compressor (12);

the bleed air from the high-pressure compressor is divided into a first part of bleed air and a second part of bleed air, wherein the first part of bleed air enters the bleed air cooling and recompression flow path (1), is subjected to temperature reduction and recompression treatment in the bleed air cooling and recompression flow path (1), is mixed with the second part of bleed air discharged by the high-pressure compressor through an ejector (8) and is discharged, and then is used for cooling the high-temperature hot end component.

2. The engine bleed air recompression cooling system of claim 1, further comprising:

and the bleed air direct discharging flow path (2) is connected with the bleed air cooling and recompression flow path (1) in parallel, and a second part of bleed air from the high-pressure compressor enters the bleed air direct discharging flow path (2) and flows through the bleed air direct discharging flow path (2) and a first part of bleed air discharged by the bleed air cooling and recompression flow path (1) are discharged after being mixed by the ejector (8).

3. The engine bleed air recompression cooling system as claimed in claim 2, further comprising:

the bleed air input pipe (3) is used for enabling bleed air from the high-pressure compressor to enter the engine bleed air recompression cooling system through the inlet end of the bleed air input pipe (3);

the outlet end of the bleed air input pipe (3) is connected with the inlet of the diverter valve (4), the outlet of the diverter valve (4) is respectively connected with the bleed air cooling and recompression flow path (1) and the bleed air direct discharge flow path (2), and bleed air from the high-pressure compressor is divided into the first part bleed air and the second part bleed air after the diverter valve (4).

4. Engine bleed air recompression cooling system according to claim 1, characterized in that the heat exchanger (11) comprises:

a precooler (111) that cools the first portion of bleed air using a first cooling medium as a heat sink;

a sub-cooler (112) that cools the first portion of the bleed air using a second cooling medium as a heat sink;

the first portion of bleed air first enters the precooler (111) for precooling and then enters the subcooler (112) for subcooling.

5. The engine bleed air recompression cooling system as claimed in claim 4, wherein the first cooling medium is bypass air.

6. Engine bleed air recompression cooling system as claimed in claim 4, wherein the second cooling medium is fuel oil.

7. The engine bleed air recompression cooling system according to claim 4, 5 or 6, wherein the precooler (111), the recompression compressor (12) and the subcooler (112) are arranged in series, and the first portion of the bleed air flows through the precooler (111), the recompression compressor (12) and the subcooler (112) in series.

8. Engine bleed air recompression cooling system as claimed in claim 4,

the precooler (111) is an air-air heat exchanger, and the precooler (111) is arranged in an outer duct of the engine;

the recooler (112) is an air-oil heat exchanger, and the recooler (112) is arranged in the inner and outer ducted inter-cabin bodies.

9. The engine bleed air recompression cooling system as claimed in claim 4, characterized in that the engine bleed air recompression cooling system further comprises a first flow path for cooling medium (6), the first flow path for cooling medium (6) comprising:

a first cooling medium inlet pipe (61) through which a first cooling medium is introduced into the first cooling medium flow path (6) via an inlet end of the first cooling medium inlet pipe (61);

a diverter ring (62) having an inlet connected to an outlet end of the first cooling medium supply pipe (61);

a first cooling medium branch pipe (63) with an inlet end connected with one of the outlets of the diverter ring (62) and an outlet end connected with the cold side inlet of the precooler (111);

a first straight coolant pipe (64) having an inlet end connected to the other outlet of the flow divider ring (62);

and a second cooling medium branch pipe (65) with an inlet end connected with the cold side outlet of the precooler (111).

10. The engine bleed air recompression cooling system according to claim 4 or 9, characterized in that the engine bleed air recompression cooling system further comprises a second flow path for cooling medium (7), the second flow path for cooling medium (7) comprising:

a second cooling medium inlet pipe (71), through which inlet end the second cooling medium enters the second cooling medium flow path (7) via the inlet end of the second cooling medium inlet pipe (71), the outlet end of the second cooling medium inlet pipe (71) being connected to the cold-side inlet of the subcooler (112);

a second coolant outlet line (72) having an inlet end connected to the cold side outlet of the subcooler (112).

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